The Aedui tribe was defeated and massacred by the combined forces of the Sequani and Arverni tribes, who had enlisted the aid of the German Suebi tribe under the Germanic king Ariovistus.
Two important routes crossed the area already during the Roman era, which allowed Julius Caesar to quickly move troops which were used to defeat Ariovistus and force his German tribes (primarily Suebi) in the province of Germania Superior to retreat across the Rhine.
Upper Germania was occupied by Gaulish tribes including the Helvetii, Sequani, Leuci, and Treveri, and, on the north bank of the middle Rhine, the remnant of the Germanic troops that had attempted to take Vesontio under Ariovistus, but who were defeated by Caesar in 58 BC.
During the first year of the Garilc Wars, Caesar sent Mettius and the Helvian Celt Gaius Valerius Troucillus as envoys to the Suebian king Ariovistus, in what is presented as a last-ditch effort to prevent a full-scale war.
His first known works are Bellum Sequanicum, a poem on Julius Caesar's campaign against Ariovistus, and some satires; these should not be confused with the Menippean Satires of the other Varro, of which some 600 fragments survive.
Gathering forces from a wide area of Germany, Ariovistus crossed the Rhine with large numbers and defeated the Aedui at the Battle of Magetobriga.